Exercise bicycle



FIG. 1 is a perspective view of an exercise bicycle showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a left end elevational view;

FIG. 4 is a right end elevational view;

FIG. 5 is a bottom plan view thereof; and

FIG. 6 is a side elevational view showing the opposite side of the exercise bicycle as shown in FIG. 1. 

The ornamental design for an exercise bicycle, as shown. 